Holographic recording system by combined use of rotational, angular, and spatial multiplexing method

회전, 각, 그리고 공간 다중화 방법을 결합사용한 홀로그램 기록 시스템

  • 신동학 (부경대학교 정보통신공학과) ;
  • 장주석 (부정대학교 정보통신공학과)
  • Published : 1998.06.01

Abstract

To increase the storage density in hologram recording, a simple scheme to obtain rotational, angular and spatial multiplexing efficiently at the same time is proposed and experimented. Both rotational multiplexing and angular multiplexing are obtained by controlling the reference beam directly by use of a pair of wedge prisms, while spatial multiplexing is obtained by shifting the recording medium in the recording plane. It is possible to get both an acute-angle geometry, in which the angle between the signal and reference beams is less than 90$^{\circ}$, and a 90$^{\circ}$ geometry, in which the angle is approximately 90$^{\circ}$. In experiment, 180 holograms were multiplexed with an acute-angle geometry where a photopolymer was used for the recording medium, and 147 holograms with 90$^{\circ}$ geometry where a Fe-doped LiNbO$_3$ crystal was used. The proposed scheme makes it easy it easy to realize a practical holographic memory system by simplifying the control of three complex mechanical motions that are necessary for the three multiplexing techniques.

홀로그램 기록에 있어서 기록저장밀도를 높이기 위해 각다중, 회전다중, 그리고 공간다중, 그리고 공간다중을 동시에 실현할 수 있는 매우 간단한 방식을 제안하고 실험하였다. 각다중과 회전다중은 두 개의 쐐기 프리즘을 이용하여 기준빔을 직접 제어함으로써 얻고, 공간다중은 기록매질을 기록평면에서 이동시킴으로써 얻었다. 기준빔과 물체빔의 사이각도가 예각인 예각기록 구조와 이것이 90$^{\circ}$인 90$^{\circ}$기록구조가 모두 구현될수 있다. 실험에서는 광풀리머를 사용한 예각기록구조로 180개의 홀로그램을 다중기록하였고, 철함유 LiNbO3 광굴절결정을 사용한 90$^{\circ}$기록구조로 147개의 홀로그램을 다중기록하였다. 우리의 방식은 3가지 다중화를 위한 복잡한 기계적 움직임의 제어를 단순함으로써 실질적 홀로그래피 메모리 시스템의 실현을 쉽게 한다.

Keywords

References

  1. Science v.265 Volume holographic storage and retrieval of digital data J. F. Heanue;M. C. Bashaw;L. Hesselink
  2. Opt. Lett. v.19 Method for holographic stroage using peristrophic multiplexing K. Cultis;A. Pu;D. Psaltis
  3. Opt. Eng. v.34 Volume holographic memory system: techniques and architectures J. H. Hong;L. McMichael;T. Y. Chang;W. Christian;E. G. Paek
  4. Appl. Opt. v.33 Three-dimensional holographic disks H. S. Li;D. Psaltis
  5. Appl. Opt. v.34 Encrypted holographic data storage based on orthogonal-phase-code multiplexing J. F. Heanue;M. C. Bashaw;L. Hesselink
  6. Optoelectronics v.10 Holographic 3-D disks D. Psaltis;A. Pu
  7. Appl. Opt. v.36 Storage of 1000 holograms with use of a dual-wavelength method E. Chuang;D. Psaltis
  8. SPIE's International Symposium on Optical Science, Engineering, and Instrumentaion Implementation of holographic storage system by combined use of rotational, angle, and shift multiplexing methods J.-S. Jang;D.-H. Shin
  9. Introduction to Fourier Optics J. W. Goodman
  10. Opt. Eng. v.35 Exposure schedule for multiplexing holograms in photopolymer films A. Pu;K. Cultis;D. Psaltis
  11. Opt. Lett. v.21 Parallel optical-feature extraction by use of rotationally multiplexed holograms J.-S. Jang;D.-H. Shin
  12. Appl. Opt. v.37 Optical implementation of the Hough transform by use of rotationally multplexed holograms D.-H. Shin;J.-S. Jang
  13. Appl. Opt. v.27 Adaptive optical networks using photorefractive crystal D.Psaltis;D. Brady;K. Wagner